====== Report on Sprinkler Pipe Issue (Draft) ======

Moved from [[http://www.zoology.ubc.ca/~rikblok/pmwiki/index.php/Strata/SprinklerReport]]((last modified on Wed Dec 9, 2009 @ 9:27PM))

===== Disclaimer =====

This report had been composed by the VR2611 Strata Council.  The intent of this report is to consolidate the history of events and clarify the issues around the recent sprinkler pipe breaks.  We have made every attempt to present the most current, correct, and clearly presented information possible.  Nevertheless, some errors may occur.  This report does not constitute professional advice.

===== Outline =====

(bulleted outline to be expanded into full report)

  * history
    * have had 2 exterior sprinkler pipe breaks (in late 2006 & 2008)
  * cause
    * engineer has ruled out defect in pipes and suggested it was due to freezing
    * both breaks occurred since rainscreen installation
    * both breaks occurred in rainscreened areas
    * both breaks occurred immediately after coldest days since rainscreening
    * there were colder days before rainscreening but no breaks occurred
    * rainscreen contributing to freezing
    * rainscreening didn't modify sprinkler pipes except to lengthen dry sidewalls (need to confirm this with RJC; if they did make changes were they inspected and "to code"?)
    * but rainscreen has air gap that allows cold air to flow back from dry sidewall to wet pipe
    * vapour barrier was installed so that wet pipe is on exterior side.  The wet pipe is trapped on the "cold" side of the vapour barrier.  We've been told by consultants that this is incorrect--it should be on the interior side.  (Q: Was this by design or was it installed incorrectly by the contractor?  Need to see RJC's design details.)
    * cold air is causing uneven contraction at junction between iron and PVC pipes
    * water in pipe may be freezing
    * pipe fails due to pressure at junction (from contraction or freezing)
  * strata opinion
    * strata believes solution to pipe freezing is to warm wet pipe via three modifications
    * first, seal/insulate around dry sidewall to prevent ingress of cold air
    * second, move vapour barrier so wet pipe is on interior side
    * don't need to worry about condensation on the pipe because it will warm (standing water) so humidity won't condense on outside [communication from Ezra Zapanta, Escape Fire Protection, Dec 8, 2009]
    * will effectively revert to thermal conditions before rainscreen (or better: the vapour barrier may always have been on the wrong side)
    * there were no breaks before the rainscreen (even in much colder weather) so should be sufficient
    * but to be sure, suggest a third modification
    * put hole in valence to let warm air in.  Can cover with register
    * need to make sure there is fire retardant drywall on all sides so fire can't enter through register and spread to other suites

===== Introduction =====

(overview)

===== History =====

<div round box>
{{:strata:management:2009:sprinkler_report:wallcrosssectionoriginal.png}}

Figure 1: Probable original cross section of exterior wall and sprinkler pipe before rainscreening.  The insulated sprinkler pipe hole in the exterior wall blocks flow of cold air.  (Drawing is not to scale.)
</div>

===== Cause =====

<div round box>

^ Date        ^  Max Temperature (C) ^  Rainscreened?  ^         Outcome         ^
| 1993-01-06  |                 -3.6 |       No        |           Ok            |
| 1996-01-29  |                 -4.5 |       No        |           Ok            |
| 1996-12-26  |                 -4.7 |       No        |           Ok            |
| 1996-12-27  |                 -4.0 |       No        |           Ok            |
| 1996-12-28  |                 -7.6 |       No        |           Ok            |
| 2004-01-04  |                 -3.4 |       Yes       |           Ok            |
| 2004-01-05  |                 -3.5 |       Yes       |           Ok            |
| 2006-11-28  |                 -4.3 |       Yes       |  1st break, 2006-11-29  |
| 2008-12-19  |                 -4.3 |       Yes       |  2nd break, 2008-12-21  |
| 2008-12-20  |                 -5.3 |       Yes       |           :::           |


Table 1: The 10 coldest days (lowest daily maximum temperatures) in Vancouver since the building was completed in 1991.  Both sprinkler breaks occurred immediately after the coldest days since the rainscreening in 1999.  The failure temperature is in the range -3.5 ... -4.3 C.  (Temperature data from [[http://www.climate.weatheroffice.ec.gc.ca/climateData/dailydata_e.html | Environment Canada]] .)
</div>

<div round box>
{{:strata:management:2009:sprinkler_report:dailytemps.png?600}}

Figure 2: Daily maximum temperatures since the building was completed in 1991.   Both sprinkler breaks occurred immediately after the coldest days since the rainscreening in 1999.  The failure temperature is in the range -3.5 ... -4.3 C.  No breaks occurred before the rainscreening despite colder weather.  (Temperature data from [[http://www.climate.weatheroffice.ec.gc.ca/climateData/dailydata_e.html | Environment Canada]] .)
</div>

<div round box>
|  {{:strata:management:2009:sprinkler_report:sprinkler_pipe_in_small_office_009_small.jpg?200}}  |  {{:strata:management:2009:sprinkler_report:sprinkler_pipe_in_small_office_010_small.jpg?200}}  |  {{:strata:management:2009:sprinkler_report:sprinkler_pipe_in_small_office_017_small.jpg?200}}  |
|  (a) Open bulkhead in small office with probe inserted. | (b) Side profile of (a) showing probe depth. | %%(c)%% As (a) but with light shining into pipe hole showing significant reflection (indicating a large gap). |
|  {{:strata:management:2009:sprinkler_report:sprinkler_pipe_in_small_office_018_small.jpg?200}}  |  {{:strata:management:2009:sprinkler_report:sprinkler_pipe_in_small_office_019_small.jpg?200}}  |  {{:strata:management:2009:sprinkler_report:sprinkler_pipe_in_small_office_021_small.jpg?200}}  |
| (d) As (a) but with probe on other side of pipe. | (e) Side profile of (d). | (f) Removed sprinkler pipe from most recent break with probe showing the probe was inserted all the way to the sprinkler head. |

Figure 3: Photos of open bulkhead in small office with probe inserted and removed sprinkler pipe from most recent break.  The probe was easily inserted the entire length of the pipe to the sprinkler head without encountering any resistance.  No insulation was found.
</div>

<div round box>
{{:strata:management:2009:sprinkler_report:wallcrosssectioncurrent.png|}}

Figure 4: Current cross section of rainscreen, exterior wall, and sprinkler pipe.  Shows flow of cold air through exterior wall directly to wet pipe, causing freezing and pipe failure.  (Drawing is not to scale.)
</div>

===== Strata Opinion =====

<div round box>
{{:strata:management:2009:sprinkler_report:wallcrosssectionrecommended.png|}}

Figure 5: In the opinion of the strata insulating the sprinkler pipe hole in the exterior wall to block flow of cold air may prevent future breaks.  (Drawing is not to scale.)
</div>

===== Conclusion =====

(review)
